I stumbled here looking to see if there was any way to run GTR2/Power & Glory on Ubuntu with my G25 wheel. Not looking good, but just to correct something said earlier in the thread; I believe GTR2, unlike GTR1 and GT Legends, uses Securom copy protection rather than Starforce. In fact, that's one of the selling points of the Power & Glory mod, while you have to own a copy of GT Legends to install it, you do not actually have to install GT Legends, thereby keeping your system Starforce free while still getting to enjoy some of those vintage sportscars.
Either way, looks like I'm still sticking with dual boot.